﻿#region << 版 本 注 释 >>
/*
 * ======================================================
 * Copyright(c) 2012-2015 Zeal Fung, All Rights Reserved.
 * ======================================================
 *  
 * 【当前类文件的功能】
 *  
 *  
 * 作者：[冯梓易]   时间：2013/12/8 星期日 7:40:09
 * 文件名：SqlLiteDBHelper
 * 版本：V1.0.0
 * 
 * 修改者：           时间：               
 * 修改说明：
 * ======================================================
*/
#endregion
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SQLite;
using System.Data.Common;

namespace CreateTable
{
    public class SqlLiteDBHelper
    {
        private string connectionString = string.Empty;
        /// <summary> 
        /// 构造函数 
        /// </summary> 
        /// <param name="dbPath">SQLite数据库文件路径</param> 
        public SqlLiteDBHelper(string dbPath)
        {
            this.connectionString = "Data Source=" + dbPath + ";Password=2014Andwho0107";
        }
        /// <summary> 
        /// 创建SQLite数据库文件 
        /// </summary> 
        /// <param name="dbPath">要创建的SQLite数据库文件路径</param> 
        public static void CreateDB(string dbPath)
        {
            SQLiteConnection.CreateFile(dbPath);
            //using (SQLiteConnection connection = new SQLiteConnection("Data Source=" + dbPath)) 
            //{ 
            //        connection.Open(); 
            //        using (SQLiteCommand command = new SQLiteCommand(connection)) 
            //        { 
            //                command.CommandText = "CREATE TABLE Demo(id integer NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE)"; 
            //                command.ExecuteNonQuery(); 
            //                command.CommandText = "DROP TABLE Demo"; 
            //                command.ExecuteNonQuery(); 
            //        } 
            //} 
        }

        public bool ChangePassword(string newpsd)
        {
            try
            {
                using (SQLiteConnection connection = new SQLiteConnection(connectionString))
                {
                    connection.Open();
                    connection.ChangePassword(newpsd);
                    connection.Close();
                    return true;
                }
            }
            catch
            {
                return false;
            }
        }
        /// <summary> 
        /// 对SQLite数据库执行增删改操作，返回受影响的行数。 
        /// </summary> 
        /// <param name="sql">要执行的增删改的SQL语句</param> 
        /// <param name="parameters">执行增删改语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param> 
        /// <returns></returns> 
        public int ExecuteNonQuery(string sql, SQLiteParameter[] parameters)
        {
            int affectedRows = 0;
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                connection.Open();
                using (DbTransaction transaction = connection.BeginTransaction())
                {
                    using (SQLiteCommand command = new SQLiteCommand(connection))
                    {
                        command.CommandText = sql;
                        if (parameters != null)
                        {
                            command.Parameters.AddRange(parameters);
                        }
                        affectedRows = command.ExecuteNonQuery();
                    }
                    transaction.Commit();
                }
            }
            return affectedRows;
        }
        /// <summary> 
        /// 执行一个查询语句，返回一个关联的SQLiteDataReader实例 
        /// </summary> 
        /// <param name="sql">要执行的查询语句</param> 
        /// <param name="parameters">执行SQL查询语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param> 
        /// <returns></returns> 
        public SQLiteDataReader ExecuteReader(string sql, SQLiteParameter[] parameters)
        {
            SQLiteConnection connection = new SQLiteConnection(connectionString);
            SQLiteCommand command = new SQLiteCommand(sql, connection);
            if (parameters != null)
            {
                command.Parameters.AddRange(parameters);
            }
            connection.Open();
            return command.ExecuteReader(CommandBehavior.CloseConnection);
        }
        /// <summary> 
        /// 执行一个查询语句，返回一个包含查询结果的DataTable 
        /// </summary> 
        /// <param name="sql">要执行的查询语句</param> 
        /// <param name="parameters">执行SQL查询语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param> 
        /// <returns></returns> 
        public DataTable ExecuteDataTable(string sql, SQLiteParameter[] parameters)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand command = new SQLiteCommand(sql, connection))
                {
                    if (parameters != null)
                    {
                        command.Parameters.AddRange(parameters);
                    }
                    SQLiteDataAdapter adapter = new SQLiteDataAdapter(command);
                    DataTable data = new DataTable();
                    adapter.Fill(data);
                    return data;
                }
            }

        }
        /// <summary> 
        /// 执行一个查询语句，返回查询结果的第一行第一列 
        /// </summary> 
        /// <param name="sql">要执行的查询语句</param> 
        /// <param name="parameters">执行SQL查询语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param> 
        /// <returns></returns> 
        public Object ExecuteScalar(string sql, SQLiteParameter[] parameters)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand command = new SQLiteCommand(sql, connection))
                {
                    if (parameters != null)
                    {
                        command.Parameters.AddRange(parameters);
                    }
                    SQLiteDataAdapter adapter = new SQLiteDataAdapter(command);
                    DataTable data = new DataTable();
                    adapter.Fill(data);
                    return data;
                }
            }
        }
        /// <summary> 
        /// 查询数据库中的所有数据类型信息 
        /// </summary> 
        /// <returns></returns> 
        public DataTable GetSchema()
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                connection.Open();
                DataTable data = connection.GetSchema("TABLES");
                connection.Close();
                //foreach (DataColumn column in data.Columns) 
                //{ 
                //        Console.WriteLine(column.ColumnName); 
                //} 
                return data;
            }
        }


    }
}
